The maximum time, T, in minutes, a scuba diver can rise without stopping for decompression on the way to the surface is modeled by the equation T (d) = 525/d-10 , d > 10, where d is the depth of the dive in metres.

a) sketch a graph of this relationship.

b) use the graph to show how deep a diver can dive for the maximum time to be less than 30 min.